Earlier today the radar showed strange echoes across the Connecticut shoreline from North Branford to Salem. It was clear it wasn’t rain being picked up by the radar. How do we know that? For one, it wasn’t cloudy. Secondly, dual polarization radar products indicated (with correlation coefficient values near 0.65) these radar echoes were likely biological targets – NOT meteorological targets.
We frequently see birds on radar around sunrise when they take off. We even see insects when they get caught up in various wind shifts. Today’s echoes were unusual in their persistence and the huge area they took up across the shoreline. Toward sunset it was clear these were indeed biological targets. The birds were flocking to the Connecticut River just before dusk.
How cool is that? On my Facebook page Paul Shipman thought the birds may be Tree Swallows that visit the lower Connecticut River this time of year. As it turns out Paul was right and tree swallows were the culprit behind the mysterious bird on radar.
According to the Hartford Courant as many as 500,000 Tree Swallows land shortly before sunset on Goose Island in Old Lyme on the Connecticut River this time of year. The radar shows the echoes disappearing right over Goose Island. This means the Tree Swallows that had been flying near 2500 feet AGL during the day (that’s where the radar beam is) were diving under the radar beam. Here’s a close up look at where the Tree Swallows were landing in Old Lyme.
Apparently CT River Quest out of Haddam offers cruises to see the Tree Swallows landing on Goose Island around sunset. Based on what I’ve seen here on radar it must be an incredible site!
I’m excited to see if our 500,000 avian friends return tomorrow!